Bra Size Calculator
Enter your measurements to get a starting bra size. For best accuracy, measure while braless or in a non-padded bra.
This tool provides an estimate. Brand sizing, breast shape, and style can affect your final fit.
How to Use This “Find My Bra Size” Calculator
A good fit starts with accurate measurements. This calculator uses your underbust and bust values to estimate a band size and cup size. The result is a starting point you can use while shopping online or in-store.
If you can provide standing, leaning, and lying bust measurements, the estimate may be more balanced because it averages your bust volume across positions.
How to Measure at Home
1) Snug Underbust
Wrap a soft measuring tape directly under your bust, keeping it level all the way around. Pull it snug, but not painfully tight. Exhale normally before recording the number.
2) Standing Bust
Measure around the fullest part of your bust while standing upright. Keep the tape level and avoid compressing breast tissue.
3) Leaning Bust (Optional)
Lean forward at roughly 90 degrees and measure at the fullest point. This can capture softer tissue and improve cup estimation.
4) Lying Bust (Optional)
Lie on your back and measure around the fullest point once more. This helps smooth out measurement differences.
How the Calculator Determines Your Size
- Band size: based on your snug underbust measurement, rounded to standard band increments.
- Cup size: determined by the difference between bust and band measurements.
- Sister sizes: nearby alternatives that keep similar cup volume with a different band fit.
If your result feels close but not perfect, try one sister size up and one sister size down.
Common Fit Problems (and What They Usually Mean)
Band rides up in back
The band is likely too loose. Try a smaller band and possibly a larger cup letter to keep volume similar.
Straps digging into shoulders
Straps should support lightly, not carry all the weight. A firmer band usually helps.
Cup overflow (spillage)
Try a larger cup size. If the band already feels tight, move to a sister size with a larger cup and larger band.
Gaping cups
Try a smaller cup or a style better suited to your shape (for example, balconette vs. plunge).
Helpful Tips for Better Accuracy
- Measure twice and use the average.
- Use a flexible, non-stretch tape.
- Check your size every 6–12 months.
- Re-measure after weight changes, pregnancy, or hormonal shifts.
- Remember that different brands fit differently.
Frequently Asked Questions
Is this calculator accurate?
It is accurate as a starting estimate, not a guaranteed final fit. Try nearby sizes and styles for best results.
Why does my size change across brands?
Each brand uses slightly different patterns and grading. Cup shape, wire width, and fabric stretch all matter.
Should I choose comfort or exact measurement?
Comfort and support should guide your final choice. A technically correct size that feels bad is not the right size for you.
Final Thoughts
Use this calculator to quickly narrow your options and reduce trial-and-error. Once you know your estimated size and sister sizes, you can shop more confidently and focus on fit, comfort, and support.